Boot upper



FIG. 1 is a perspective view of a boot upper showing my new design;

FIG. 2 is a right side view of thereof;

FIG. 3 is a left side view thereof;

FIG. 4 is a bottom view thereof;

FIG. 5 is a rear view thereof;

FIG. 6 is a front view thereof; and,

FIG. 7 is a top view thereof.

The larger, dashed lines (in FIG. 4, for example) shown in the drawings are for illustrative purposes only and form no part of the claimed design. The smaller, dotted lines used throughout the drawings represent stitching. 

The ornamental design for a boot upper, as shown and described. 